Platform assemblies are used during construction in order to support workers and equipment at desired elevations. Platforms of this kind include stationary scaffolding that requires a significant amount of labor to set up and subsequently modify should a change in elevation be desired. As such, in order to save both time and labor elevating platform assemblies are useful for quickly and effortless moving workers and equipment to desired elevations. Elevating platform assemblies typically include a mast that is erected adjacent to the object being constructed or assembled. The mast carries a platform onto which the workers or equipment are supported. The platform can be moved vertically along the mast to a particular point and can be locked into place once the particular elevation is achieved.
One known way of moving the platform up and down along the mast involves the use of a drum and cable system. Here, a cable is attached to the platform and is wound around a drum that is located either on the mast or on the ground. Although suitable for their intended purpose, cable and drum systems are typically disfavored as a result of certain disadvantageous present in these types of designs.
Another means used to motivate platforms vertically along the mast is a rack and pinion drive assembly. The rack is oriented in a vertical manner along a portion of the mast. A plurality of drive pinions are rotatably mounted onto the platform. An appropriate driving means, such as a motor, is located on the platform and rotate the pinions in order to raise and lower the platform along the rack. A safety device such as an overspeed pinion can be incorporated in order to brake the platform along the rack should the platform travel too quickly.
Although rack and pinion systems are capable of moving a platform along the mast, the drive mechanism for the system is included on the platform. The pinion driving mechanism may take up space on the platform that could be used for holding workers or equipment. Additionally, should something happen to the pinion driving mechanism it cannot be repaired from the ground thus forcing additional, potentially costly, measures to be taken to remove the workers and equipment from the platform and to then access the platform to make the appropriate repairs. Also, the pinion and gearing components in the driving mechanism can be damaged through side impacts of the platform during loading and the construction process. These impacts on components could cause their failure, result in their damage thus reducing overall performance, and necessitate costly repair. As such, there remains room for variation and improvement within the art.